LibJS+Everywhere: Allow Cell::initialize overrides to throw OOM errors

Note that as of this commit, there aren't any such throwers, and the
call site in Heap::allocate will drop exceptions on the floor. This
commit only serves to change the declaration of the overrides, make sure
they return an empty value, and to propagate OOM errors frm their base
initialize invocations.

Userland/Libraries/LibWeb/DOM/AbortController.cpp

@@ -25,10 +25,12 @@ AbortController::AbortController(JS::Realm& realm, JS::NonnullGCPtr<AbortSignal>
 
 AbortController::~AbortController() = default;
 
-void AbortController::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> AbortController::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::AbortControllerPrototype>(realm, "AbortController"));
+
+    return {};
 }
 
 void AbortController::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/AbortController.h

@@ -28,7 +28,7 @@ public:
 private:
     AbortController(JS::Realm&, JS::NonnullGCPtr<AbortSignal>);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     // https://dom.spec.whatwg.org/#abortcontroller-signal

Userland/Libraries/LibWeb/DOM/AbortSignal.cpp

@@ -22,10 +22,12 @@ AbortSignal::AbortSignal(JS::Realm& realm)
 {
 }
 
-void AbortSignal::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> AbortSignal::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::AbortSignalPrototype>(realm, "AbortSignal"));
+
+    return {};
 }
 
 // https://dom.spec.whatwg.org/#abortsignal-add

Userland/Libraries/LibWeb/DOM/AbortSignal.h

@@ -43,7 +43,7 @@ public:
 private:
     explicit AbortSignal(JS::Realm&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(JS::Cell::Visitor&) override;
 
     // https://dom.spec.whatwg.org/#abortsignal-abort-reason

Userland/Libraries/LibWeb/DOM/AbstractRange.cpp

@@ -21,10 +21,12 @@ AbstractRange::AbstractRange(Node& start_container, u32 start_offset, Node& end_
 
 AbstractRange::~AbstractRange() = default;
 
-void AbstractRange::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> AbstractRange::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::AbstractRangePrototype>(realm, "AbstractRange"));
+
+    return {};
 }
 
 void AbstractRange::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/AbstractRange.h

@@ -36,7 +36,7 @@ public:
 protected:
     AbstractRange(Node& start_container, u32 start_offset, Node& end_container, u32 end_offset);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     JS::NonnullGCPtr<Node> m_start_container;

Userland/Libraries/LibWeb/DOM/Attr.cpp

@@ -31,10 +31,12 @@ Attr::Attr(Document& document, QualifiedName qualified_name, DeprecatedString va
 {
 }
 
-void Attr::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Attr::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::AttrPrototype>(realm, "Attr"));
+
+    return {};
 }
 
 void Attr::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Attr.h

@@ -45,7 +45,7 @@ public:
 private:
     Attr(Document&, QualifiedName, DeprecatedString value, Element const*);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     QualifiedName m_qualified_name;

Userland/Libraries/LibWeb/DOM/CDATASection.cpp

@@ -16,10 +16,12 @@ CDATASection::CDATASection(Document& document, DeprecatedString const& data)
 
 CDATASection::~CDATASection() = default;
 
-void CDATASection::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> CDATASection::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::CDATASectionPrototype>(realm, "CDATASection"));
+
+    return {};
 }
 
 }

Userland/Libraries/LibWeb/DOM/CDATASection.h

@@ -23,7 +23,7 @@ public:
 private:
     CDATASection(Document&, DeprecatedString const&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 };
 
 template<>

Userland/Libraries/LibWeb/DOM/CharacterData.cpp

@@ -19,10 +19,12 @@ CharacterData::CharacterData(Document& document, NodeType type, DeprecatedString
 {
 }
 
-void CharacterData::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> CharacterData::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::CharacterDataPrototype>(realm, "CharacterData"));
+
+    return {};
 }
 
 // https://dom.spec.whatwg.org/#dom-characterdata-data

Userland/Libraries/LibWeb/DOM/CharacterData.h

@@ -36,7 +36,7 @@ public:
 protected:
     CharacterData(Document&, NodeType, DeprecatedString const&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 
 private:
     DeprecatedString m_data;

Userland/Libraries/LibWeb/DOM/CustomEvent.cpp

@@ -29,10 +29,12 @@ CustomEvent::CustomEvent(JS::Realm& realm, DeprecatedFlyString const& event_name
 
 CustomEvent::~CustomEvent() = default;
 
-void CustomEvent::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> CustomEvent::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::CustomEventPrototype>(realm, "CustomEvent"));
+
+    return {};
 }
 
 void CustomEvent::visit_edges(JS::Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/CustomEvent.h

@@ -28,7 +28,7 @@ public:
     // https://dom.spec.whatwg.org/#dom-customevent-detail
     JS::Value detail() const { return m_detail; }
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(JS::Cell::Visitor&) override;
 
     void init_custom_event(DeprecatedString const& type, bool bubbles, bool cancelable, JS::Value detail);

Userland/Libraries/LibWeb/DOM/DOMImplementation.cpp

@@ -31,10 +31,12 @@ DOMImplementation::DOMImplementation(Document& document)
 
 DOMImplementation::~DOMImplementation() = default;
 
-void DOMImplementation::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> DOMImplementation::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::DOMImplementationPrototype>(realm, "DOMImplementation"));
+
+    return {};
 }
 
 void DOMImplementation::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/DOMImplementation.h

@@ -30,7 +30,7 @@ public:
 private:
     explicit DOMImplementation(Document&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     Document& document() { return m_document; }

Userland/Libraries/LibWeb/DOM/DOMTokenList.cpp

@@ -68,10 +68,12 @@ DOMTokenList::DOMTokenList(Element const& associated_element, DeprecatedFlyStrin
     associated_attribute_changed(value);
 }
 
-void DOMTokenList::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> DOMTokenList::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::DOMTokenListPrototype>(realm, "DOMTokenList"));
+
+    return {};
 }
 
 void DOMTokenList::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/DOMTokenList.h

@@ -45,7 +45,7 @@ public:
 private:
     DOMTokenList(Element const& associated_element, DeprecatedFlyString associated_attribute);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     WebIDL::ExceptionOr<void> validate_token(StringView token) const;

Userland/Libraries/LibWeb/DOM/Document.cpp

@@ -314,10 +314,12 @@ Document::~Document()
     HTML::main_thread_event_loop().unregister_document({}, *this);
 }
 
-void Document::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Document::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::DocumentPrototype>(realm, "Document"));
+
+    return {};
 }
 
 void Document::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Document.h

@@ -450,7 +450,7 @@ public:
     DeprecatedString dump_accessibility_tree_as_json();
 
 protected:
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
 private:

Userland/Libraries/LibWeb/DOM/DocumentFragment.cpp

@@ -14,10 +14,12 @@ DocumentFragment::DocumentFragment(Document& document)
 {
 }
 
-void DocumentFragment::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> DocumentFragment::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::DocumentFragmentPrototype>(realm, "DocumentFragment"));
+
+    return {};
 }
 
 void DocumentFragment::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/DocumentFragment.h

@@ -33,7 +33,7 @@ public:
 protected:
     explicit DocumentFragment(Document& document);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
 private:

Userland/Libraries/LibWeb/DOM/DocumentType.cpp

@@ -19,10 +19,12 @@ DocumentType::DocumentType(Document& document)
 {
 }
 
-void DocumentType::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> DocumentType::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::DocumentTypePrototype>(realm, "DocumentType"));
+
+    return {};
 }
 
 }

Userland/Libraries/LibWeb/DOM/DocumentType.h

@@ -36,7 +36,7 @@ public:
 private:
     explicit DocumentType(Document&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 
     DeprecatedString m_name;
     DeprecatedString m_public_id;

Userland/Libraries/LibWeb/DOM/Element.cpp

@@ -61,12 +61,14 @@ Element::Element(Document& document, DOM::QualifiedName qualified_name)
 
 Element::~Element() = default;
 
-void Element::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Element::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::ElementPrototype>(realm, "Element"));
 
     m_attributes = NamedNodeMap::create(*this);
+
+    return {};
 }
 
 void Element::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Element.h

@@ -251,7 +251,7 @@ public:
 
 protected:
     Element(Document&, DOM::QualifiedName);
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 
     virtual void children_changed() override;
     virtual i32 default_tab_index_value() const;

Userland/Libraries/LibWeb/DOM/Event.cpp

@@ -41,10 +41,12 @@ Event::Event(JS::Realm& realm, DeprecatedFlyString const& type, EventInit const&
 {
 }
 
-void Event::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Event::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::EventPrototype>(realm, "Event"));
+
+    return {};
 }
 
 void Event::visit_edges(Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Event.h

@@ -146,7 +146,7 @@ public:
 protected:
     void initialize_event(DeprecatedString const&, bool, bool);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Visitor&) override;
 
 private:

Userland/Libraries/LibWeb/DOM/HTMLCollection.cpp

@@ -27,10 +27,12 @@ HTMLCollection::HTMLCollection(ParentNode& root, Function<bool(Element const&)>
 
 HTMLCollection::~HTMLCollection() = default;
 
-void HTMLCollection::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> HTMLCollection::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::HTMLCollectionPrototype>(realm, "HTMLCollection"));
+
+    return {};
 }
 
 void HTMLCollection::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/HTMLCollection.h

@@ -47,7 +47,7 @@ public:
 protected:
     HTMLCollection(ParentNode& root, Function<bool(Element const&)> filter);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 
     JS::NonnullGCPtr<ParentNode> root() { return *m_root; }
 

Userland/Libraries/LibWeb/DOM/MutationObserver.cpp

@@ -31,10 +31,12 @@ MutationObserver::MutationObserver(JS::Realm& realm, JS::GCPtr<WebIDL::CallbackT
 
 MutationObserver::~MutationObserver() = default;
 
-void MutationObserver::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> MutationObserver::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::MutationObserverPrototype>(realm, "MutationObserver"));
+
+    return {};
 }
 
 void MutationObserver::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/MutationObserver.h

@@ -52,7 +52,7 @@ public:
 private:
     MutationObserver(JS::Realm&, JS::GCPtr<WebIDL::CallbackType>);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     // https://dom.spec.whatwg.org/#concept-mo-callback

Userland/Libraries/LibWeb/DOM/MutationRecord.cpp

@@ -33,10 +33,12 @@ MutationRecord::MutationRecord(JS::Realm& realm, DeprecatedFlyString const& type
 
 MutationRecord::~MutationRecord() = default;
 
-void MutationRecord::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> MutationRecord::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::MutationRecordPrototype>(realm, "MutationRecord"));
+
+    return {};
 }
 
 void MutationRecord::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/MutationRecord.h

@@ -32,7 +32,7 @@ public:
 private:
     MutationRecord(JS::Realm& realm, DeprecatedFlyString const& type, Node& target, NodeList& added_nodes, NodeList& removed_nodes, Node* previous_sibling, Node* next_sibling, DeprecatedString const& attribute_name, DeprecatedString const& attribute_namespace, DeprecatedString const& old_value);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     DeprecatedFlyString m_type;

Userland/Libraries/LibWeb/DOM/NamedNodeMap.cpp

@@ -25,10 +25,12 @@ NamedNodeMap::NamedNodeMap(Element& element)
 {
 }
 
-void NamedNodeMap::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> NamedNodeMap::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::NamedNodeMapPrototype>(realm, "NamedNodeMap"));
+
+    return {};
 }
 
 void NamedNodeMap::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/NamedNodeMap.h

@@ -56,7 +56,7 @@ public:
 private:
     explicit NamedNodeMap(Element&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     Element& associated_element() { return *m_element; }

Userland/Libraries/LibWeb/DOM/NodeIterator.cpp

@@ -21,10 +21,12 @@ NodeIterator::NodeIterator(Node& root)
 
 NodeIterator::~NodeIterator() = default;
 
-void NodeIterator::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> NodeIterator::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::NodeIteratorPrototype>(realm, "NodeIterator"));
+
+    return {};
 }
 
 void NodeIterator::finalize()

Userland/Libraries/LibWeb/DOM/NodeIterator.h

@@ -37,7 +37,7 @@ public:
 private:
     explicit NodeIterator(Node& root);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
     virtual void finalize() override;
 

Userland/Libraries/LibWeb/DOM/NodeList.cpp

@@ -17,10 +17,12 @@ NodeList::NodeList(JS::Realm& realm)
 
 NodeList::~NodeList() = default;
 
-void NodeList::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> NodeList::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::NodeListPrototype>(realm, "NodeList"));
+
+    return {};
 }
 
 JS::Value NodeList::item_value(size_t index) const

Userland/Libraries/LibWeb/DOM/NodeList.h

@@ -27,7 +27,7 @@ public:
 protected:
     explicit NodeList(JS::Realm&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 };
 
 }

Userland/Libraries/LibWeb/DOM/ProcessingInstruction.cpp

@@ -17,10 +17,12 @@ ProcessingInstruction::ProcessingInstruction(Document& document, DeprecatedStrin
 {
 }
 
-void ProcessingInstruction::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> ProcessingInstruction::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::ProcessingInstructionPrototype>(realm, "ProcessingInstruction"));
+
+    return {};
 }
 
 }

Userland/Libraries/LibWeb/DOM/ProcessingInstruction.h

@@ -24,7 +24,7 @@ public:
 private:
     ProcessingInstruction(Document&, DeprecatedString const& data, DeprecatedString const& target);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 
     DeprecatedString m_target;
 };

Userland/Libraries/LibWeb/DOM/Range.cpp

@@ -66,10 +66,12 @@ Range::~Range()
     live_ranges().remove(this);
 }
 
-void Range::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Range::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::RangePrototype>(realm, "Range"));
+
+    return {};
 }
 
 void Range::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Range.h

@@ -93,7 +93,7 @@ private:
     explicit Range(Document&);
     Range(Node& start_container, u32 start_offset, Node& end_container, u32 end_offset);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     Node& root();

Userland/Libraries/LibWeb/DOM/StaticRange.cpp

@@ -35,10 +35,12 @@ WebIDL::ExceptionOr<StaticRange*> StaticRange::construct_impl(JS::Realm& realm,
     return realm.heap().allocate<StaticRange>(realm, *init.start_container, init.start_offset, *init.end_container, init.end_offset).ptr();
 }
 
-void StaticRange::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> StaticRange::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::StaticRangePrototype>(realm, "StaticRange"));
+
+    return {};
 }
 
 }

Userland/Libraries/LibWeb/DOM/StaticRange.h

@@ -29,7 +29,7 @@ public:
     StaticRange(Node& start_container, u32 start_offset, Node& end_container, u32 end_offset);
     virtual ~StaticRange() override;
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
 };
 
 }

Userland/Libraries/LibWeb/DOM/Text.cpp

@@ -24,10 +24,12 @@ Text::Text(Document& document, NodeType type, DeprecatedString const& data)
 {
 }
 
-void Text::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> Text::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::TextPrototype>(realm, "Text"));
+
+    return {};
 }
 
 void Text::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/Text.h

@@ -38,7 +38,7 @@ protected:
     Text(Document&, DeprecatedString const&);
     Text(Document&, NodeType, DeprecatedString const&);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
 private:

Userland/Libraries/LibWeb/DOM/TreeWalker.cpp

@@ -22,10 +22,12 @@ TreeWalker::TreeWalker(Node& root)
 
 TreeWalker::~TreeWalker() = default;
 
-void TreeWalker::initialize(JS::Realm& realm)
+JS::ThrowCompletionOr<void> TreeWalker::initialize(JS::Realm& realm)
 {
-    Base::initialize(realm);
+    MUST_OR_THROW_OOM(Base::initialize(realm));
     set_prototype(&Bindings::ensure_web_prototype<Bindings::TreeWalkerPrototype>(realm, "TreeWalker"));
+
+    return {};
 }
 
 void TreeWalker::visit_edges(Cell::Visitor& visitor)

Userland/Libraries/LibWeb/DOM/TreeWalker.h

@@ -39,7 +39,7 @@ public:
 private:
     explicit TreeWalker(Node& root);
 
-    virtual void initialize(JS::Realm&) override;
+    virtual JS::ThrowCompletionOr<void> initialize(JS::Realm&) override;
     virtual void visit_edges(Cell::Visitor&) override;
 
     enum class ChildTraversalType {